In conjunction with the general increase in the exploitation of hydrocarbons in marine and offshore locations, a similar increase has occurred in the number of installations on the sea bed. Such installations have most often no external protection, a fact which causes risk for damage for instance from fishing gear, and, oppositely, a risk for damaging of fishing gear and also a frequent risk for sapping of the sea bed ground below the marine construction due to erosion. A protection is therefore highly desirable in order to eliminate in a reasonable extent the beforementioned disadvantages.
The present invention is particularly suitable for protection of pipelines positioned on the sea bed. It is usually a prerequisite that such pipelines shall be dug down and be completely covered for instance by the dug up sea bed ground mass. Experience has, however, shown that the degree of down digging and coverage of the pipelines vary very much. Very often such pipelines in fact are positioned completely unprotected on the sea bed or is even in some cases "floating" or suspended above same. One can therefore conclude that it is necessary with a supplementing coverage, at least along those parts of the pipelines which are more or less uncovered.